If you like to play as Isis or any Egyptian you should pick a map where you can wall up. No towers, just walls and gates to delay them and as a trip-alarm for your troops. It's very tough to beat the Norse as Egyptians unless you wait till Heroic or preferably even Mythical first. Then it's cake because their troops are weak when faced with hordes of Champion Elephants and Chariot Archers, with 4 or 5 Priests thrown in for healing and MUs.
I've beat them on Hard on open maps where you can't wall effectively, but I had to use all of my GPs to delay them. Once you have a couple of Strongholds the only threat they pose is those pesky battering ram guys.
On the other hand, playing as Norse, if you don't rush and keep the pressure on, you'll never win for the same reason. If you let the Egyptians or Greeks advance to Mythical, you'll be swarmed by Collossi, Avengers, heck even a Son of Osiris almost levelled my entire base.
The same's true for any Civ: if you're getting beaten all the time, play a map where you can wall-up. Even as the Norse it's sometimes effective, especially when the AI chooses Norse.
The other thing you could do is choose the AI's Civ. I had a hard time as Loki in beating Hades, even with a rush so I just restarted and used new tactics. It's hard to rush when the AI quickly 'builds' a dozen archers and as Loki I could spy on the AI as it cheated. If you want to win, learn one particular Civ and then use it to beat each of the other ones.